at this time next year, on the third monday in april, the won to this great american city to run harder than ever and to cheer even louder for the 118th boston marathon! Bet on it. President obama, thursday, thoughts echoed by mayor menino day. Let's take more about where we go next? With our roundtable. Chief global affairs correspondent martha raddatz, richard haass and the editor of "the new yorker" david remnick. Senator, and the congressman, let me begin with you, whether the subject should be read his miranda rights onemy cobah abouts. Also, the fact that his travel back to his hometown, that was a muslim area, could have been radicalized -- that was his brother. That was his brother, though, that's correct. We're talking about the two of them together, as to what why it happened. And I think, we got to keep that option open until we find out whether or not there was a connection to the terrorist organization. Do you agree? I'll agree, there is no question. The public safety exception is that we should utilize and that we should get all of the information available to us. How long does that public safety exception hold? Even though the guy is lying flat on his back in a hospital bed? Obviously, there are some communications right now because he can't talk. Obviously, we can do some other things. We still, I believe, have enough evidence, I don't think we can solely arrive on mirandizing this candidate. He's clearly one of those individuals we have, what we need to do is collect the evidence, turn it over to the u.S. Attorney, prosecute him to fullest extent of the law. You don't think he should be treated as an enemy combatant going forward? No, no. Unless there's a link. Mayor menino mentioned that he may be never be able to talk. Information on his wounds? Information we have, there was a shot to the throat and it's questionable whether -- whether he'll be able to talk again, doesn't mean he can't communicate. Right now, he's in a condition where they can't get any information from him. Thank you very much. Let's talk about the terrt threat we're facing right now. Martha raddatz, the possibility of connection to overseas groups or al qaeda connection? No evidence of that yet, but that could be the nightmare scenario. It is. That's where they're focused on now. Whether there's an overseas connection, in terms of where the older brother got any training there, I think we have to talk about these missing years in a way, the russians alerted the u.S. That he was radicalized, that he was involved in groups, somewhere over there, they believed. That was 2011 when the fbi inveated. At the request of the russians? At the request of the russians. Then he goes back. What happened before 2011? To alert the russians? Was it visiting internet sites? A specific group they were concerned about they knew he was communicating with? Those missing years are what their going to concentrate on and whether they that continued. And david remnick, you spent a lot of time in russia for "the washington post." Everybody's going to be looking at these six months. We know that his parents went back to live in russia for some time. From the mother, we also heard that the fbi was on top on tamerlan for several years. The parents moved back to dagestan, because the father wants to die there, he's very, very sick. That's the circumstance, as far as we know. We have no link between the parents and anything like the jihadist interest at all. In fact, they seem to be utterly shocked and in disbelief. The older brother had been visiting jihadist websites. I spent friday looking at his youtube list is extremely frightening, ominous websites, pro-al qaeda. Going on of the evils of the magic of harry potter. The twitter feed of the younger brother, has hints of this kind of thing as well. So, there is no question that they weren't merely religious, they were but interested in jihadist struggle, global jihadist. The slogan in that region, in dagestan and in chechnya -- although, a statement coming out today from one of groups in dagestan, saying our enemy is not the united states, our enemy is russia. Richard haass, that area hot bed of various islamic cells. But the main fight for the chechens in dagestan has been against the russian leadership. That's true. Terrorism can be global but also local. Historically it was much more local than international. So, I think the chechen connection is probably secondary here. You don't have to travel to be influenced by what is going on in torld. The internet does it all for you. So, I think -- yeah, the foreign connection is important. Probably more important is the alienation and the vulnerable of these kind of young people in the united states but they're not integrated into the american society. What this remains me of the 2005 london bombings, where you have young muslim, grew up in britain, they went to british schools, they had some foreign connections to pakistan but they were alienated from society. We, as americans need to look very hard to make sure this thing doesn't happen and the leaders of these communities protect us from them. What do they get when they're radicalized? They get this sense of importance, this sense of mission. They fit in themselves. They play out a fantasy of fury and romantic nationalism for a place they never really lived. In fact, if it's chechen nationalism or some global jihad they're interested in, there's no sense that these kids are well read in this. Or well versed. Is especially the young brother. He spent most of his time in america. The connection between their rather idiotic interest and the evil acts they carried out -- let me bring it back to the legislators here. The member of senate -- you have been able to develop any information that gives you a of radicalization occurred? Well, that's what's being investigated right now and as everything is being searched. All of the intelligence agencies are playing in this, trying to find out whether there's a connection, it's a really important step that needs to be made. If there's a connection, whether or not there is, isn't, I think what happened here, the signal have been sent. Those who want to harm americans it is that we'll do everything we can to prevent this from happening. If you take on america, america is going to take you on. It's not just the intelligence agencies and the law enforcement. I commend the coordination that pulled this thing together. But, it's americans, the runners in the race ran to help the victims, boston response was extraordinary, like new york post 9/11. The signal is -- don't mess with you, we'll chase you to the ends of earth if we have to. The problem is, they were just in the neighborhood. One of the problems, george, how do you deal with people who are already in this country, how do you deal with their radicalization? Is it on the internet? Is it their associations with other friends? That's something we're having to deal with every day. We have dealt with international terrorists trying to get here. We can't spend enough money to defend ourselves against that, we'll go broke as a nation. That continues to be a day in, day out struggle. One of the questions that come up, perhaps, that more cities should do what new york does, and invest in a lot more counterterrorism on the ground. But, then that could get you very quickly into questions of civil liberties you start keeping eyes on neighborhoods. You're right. But new york is one of the main beneficiaries of federal dollars. If not for the federal dollars it would be very difficult for new york to be as robust as they are. Yeah, we can't lock up every young man who goes on a fantastical or nasty website, that becomes a big difficulty. In fact, we knew about this guy. The fbi talked to him in 2011. The parents readily admitted this in their interviews in dagestan. I assume in 2012, no one was tracking him when he returned. And if he visited chechnya what he was doing there. If you had that red flag raised I think you have to question why wasn't he followed up? You need a longterm strategy for terrorism. What happened in boston isn't the exception. This isn't a one-off. This is glimpse of the future. This is terrorism that one, two, three people can carry out. We live in a world where powers diffused. You don't need to do something on the scale of 9/11. That turns out much less difficult to find out about. It was extremely a crude operation. Thank god, even people standing right next to the little boy who died, were relatively unscathed. If he was trained in dagestan, it wasn't high-level training. They did have other weaponry and some other bombs were discovered. But senator, what do you do, though, if no connection to a specific group is found? Irn stead, we just find that these young men were inspired by al qaeda but not directed? That's almost impossible to find? Well, it is. And that's the reality of the world we are now living in, because not only do we terrorism from abroad, we face these lone wolfs. That has revengance, a demented mind or radicalized over the internet. We're going to continue to have to understand that this is a threat to america. We need to be engaged in not only looking out for this thing, identify and see it. A kid in the classroom who is -- he wasn't a loner. He wasn't a loner. You're not going to stop every one of these. The notion is, unless you get the public buy in, the public absolutely has to understand that to address this nexus in terrorism they'll have to participate. If they see something out of to ordinary, they'll have to report it. If they don't report it, then potentially we'll miss an opportunity to identify someone. But that gets to a bigger question that was raised this week, one of the things that we saw in the wake of the bombings on monday, lot of people said things, lot of false information was being put out, we saw the both to the benefit of crowd sourcing, but also, the perils of it. Look at the front page of "the new york post," just the other day, there are two young men who had nothing to do with terrorism, "nightline" spoke to one of them after the fact. You just did this? How could you do this? Why would you even do that? You got so many people. You killed an 8-year-old. But, if you look at it, it wasn't me. He had nothing to do with it. And david remnick -- it's outrageous behavior. I have some sympathy what happened to cnn. They are all day long. They got what they legitimate sourcing telling them there was an arrest. They turned out to be wrong, they corrected their mistake, this is something slapping on the front page of the newspaper of something not confidence at all. It harms someone's life. I give that guy a lot of credit to go on television and talk to you. That takes courage. Actually, rupert murdoch said all of pictures were those distributed by the fbi. Instantly withdrawn when the fbi changed direction. It was a lousy excuse. Take responsibility and apologize? You bet. But how do we deal with this going forward, because we'll see this again and again and again. It's so easy to get that bad information out there so quickly. We actually need what the military do, we need to look at the question of lockdown, did boston about properly? How did the law enforcement cooperation go? I think journalists, media, people on the internet, need to look at what they did normal standards apply? How do you remain competitive at the same time remain responsible? We're actually, again, this is the future, it's now coming to the present. And what we're going to have to do is, we need to think through as a society, how we're going to keep ourselves safe. Martha, I felt some blowback on friday, we were on the air from 4:00 p.M. To-- a.M. To 3:00 p.M. And then, again n the everybodying, lot of people saying to me personally, why do you guys keep talking? Why do you give the attention? First of all, you had the entire city lockdown. You had to. You had this horrific event. Frankly, everyone was glued to the television. Everyone wanted to know what was happening. We have to be careful. We all have to be careful. I take the lesson of a former intelligence officer who said when I was a young man my dad took me deer hunting and we were laying there and looked out and my dad turned to me and said, son, when you go deer hunting, everything starts looking like a deer. So, we have to be careful, we have to make sure that we don't have a confirmation bias that we want something to happen. Cnn made a mistake. Law enforcement made a mistake. They said there was an explosion at the jfk library. Some speculation this was domest terrorism, domestically inspired. I worked with colin powell, he said that first reports are never complete and never accurate. Not a bad thing to remember. How about the question of the locking down the city of boston, congressman? You saw the mayor right there saying it was absolutely justified? What terrorists want to do, one of the things, other than the physical harm is the economic harm, that one day's loss of income for that area is in the hundreds of millions of dollars. So in some instance, the terrorists win there, and what we have to do is come up with the after action report. I think clearly, once we do that, there might be some alternatives. I won't second guess the governor and the mayor what they did. But one of the goals of terrorists is economic terrorism and if you look at it from that perspective they succeeded. And I take the mayor at his word that were reports and possibilities of another bombing. These guys were still at large. But there is this question whether an entire city should be shut down because that's what terrorists want. Also, an entire city is frozen with fear and anxiety, and it's horrible to say, but this is a great success for terrorism. This after action report, we have seen in other instances, new york city, after the times square bombings did not lock down. We saw that renegade former cop in l.A. Terrorizing people. D.C. Snipers, the cities did not lock down. Disruption is one of the goals of terrorists, they succeeded temporarily in this case. But you got to ke people safe. That's why it's so important to figure this out for the long-term. Again, this is coming back. What's scary about this is how relatively easy this is. And if these guys can go on the internet, to use primitive devices about it, the attention they garner is going to garner copy-cat incidents. How do we make ourselves more resilience? How do we protect ousts? How do we get better at bouncing back? It comes at a time where the al qaeda leadership top to bottom has been decimated. Which I think is frightening in a way because of exactly what happened. Because they have these fragmented groups, these splintered groups, we can't prevent attacks on soft targets. We can't. We found ourselves this week, looking around, it can happen. Not 100%. Again, people talking about let's get to the root of this, what happened to these young men? Is there anything we can do there? I don't know the answer to that. I just know you can't 100% prevent these attacks. Senator, you were talking about the effect of legislature. One of the suggestions from were op of your colleagues from iowa is, we should put the immigration reform effort on hold until we know a lot more. I agree with the senator. Why? You usually end up with bad policy if you end up doing it with an emotional reaction. We saw some things post9/11, that were enacted, if we had more rational time think this through, we would haven't had some of the pushback on it. More importantly, immigration is an issue that has dramatic economic effect on americans. I think stepping back a little bit and putting it on hold, we have a bigger issue on immigration in front of us and it's our deficit. We have a broken system that needs to be reformed. I'm afraid we'll rush through some judgments related to immigration and how it's processed. George, with respect, I think that as bad an idea as calling this enemy combatant. We have 100% rate of prosecuting terrorists. I think that's the bad idea on the senator mccain. I think the idea of delaying immigration reform, if you ask involved in immigration, this is a horrible idea to take this isolated, horrible, evil incident and make it stand for a larger politics and put immigration reform, put the brakes on that. Congressman? It's not the right thing to do. We're a nation of immigrants. I trust our government. We vet people up and down. We reviees every day. But to put it on hold is not in best interest of this country. I agree with the congressman. They'll deal with 11 million, 12 million people in this country who are still living in the shadows. We need to integrate all americans in society. We want to main stream them. I think we should move it faster. We thought about this for years, economically but also in terms of our national security, this bill will help make america safer. That's one of the lessons that we out to take from it, alienated young people, dangerous thing. Last word? Just push it back a mon two, let the emotions settle down. Let us do it in a rational way, make good judgments not based on the urgency of the moment. Congress has a way of rushing to judgments without thinking it through carefully. We're talking months here, a few weeks, not years. It needs to be done. Thank you all for a very thoughtful discussion.

This transcript has been automatically generated and may not be 100% accurate.